Heater



Patented July 2, 1946 nenni. De N.

. Gollum, deceased Henry J. De N. ltief-v Application october 7, 1942, sedermi. 461,123

The present invention relates' to heaters, particularly of the internalcombustion type and is directed more specincallyto aninternal combus- 4tion type heater well suited foruse in aircraftor other vehicles where high heat `output together withV high efficiency should preferably be ob-4 tained from a structure if-'minimum size `and weight. A heater of'v thisy general type is shown and described inmy copending application,`Serial N0. 447,345, led

June 17,1942, for Heating apparatus.

It ispone of the. objects ofthe present invention to provide a novel-internal combustion heater of the aircraft type which is extremely light in weight and economical to manufacture.

Yet another object of the present invention is to provide an internal combustion heater of extremely simple construction which is so arranged as to avoid the formation of heat'exchange system.

Yet another object of the. present invention is to provide a novel heater which burnsa mixture of liquidv fuel and air and quickly exchanges the heat of combustion lto a moving fresh air stream.

Still another object of thefpresent inventionV is to provide a novel heater having the abovementioned advantages which is extremely well adapted'to be manufactured by quantity production methods. 1 f

Yet another object of the present invention is to provide a novel `aircraft heater which usesy l a length of corrugated'tubing-as one of the principal elements of construction.y Other objects and advantages will becomel apparent from the following-description offa pre-` ferred embodiment of my invention which is-ilf lustrated in the accompanying-drawing.

In the drawing, in which similar numerals refer to similar parts throughout the several views, Flg. 1 is a side view of a heater embodying the present invention.

Fig. 2 is a longitudinal sectional view of they heater illustrated in. Fig. 1, and

Fig.` 3 is a transverse sectional view which maybe considered as takeninthe direction of the arrows along the line t-Z of Fig. 2.

The heater of the present invention is supplied with a combustible mixture which is taken into the heater through an intaketting. l0. This mixture, preferably composed ofvaporized liquid hot spots within thev aircraft. Y l

The intake uiting `m isfprovided withtribunale of small diameter tubes l2r formedtof a'material having good heat conductingy properties.1v The openings through .the-"tubes, togetherwith Y,the rspaces between adjacent tubes, provide passages of suilicient capacity sov 'that littlerestriction is offered to-the now of combustible mixturetherethrough. These tubes,` however, prevent -flame from `flashing lbaci: into the mixturefinduction,y

pipe connectdto the fitting l0 in amanner e'x-' plication. i

"plained in the before mentionedl co-pending ap- After the mixture has passed through `the tubes I2, it enters an elbow portion Hof the fitting I0 1 where combustion of the mixture is initiated; The Y ignition is .accomplished oymeansl of atem- (porarilyheated igniter, I6' of the electrically en-l ergized hot wire type. Such an igniter isde- 4 scribed in the before mentioned co-pending apy plication. The elbovr Il also is equippedwith a reigniter AI8 of the v Spiral sheetvtype, also:de` scribed in the' above mentioned co-pending application'. This reigniter is heatedtea high tem-) v perature by the name and, therefore`," serves to reignite Vthe combustible mixture if combustion should.l for any reason fail afterfthe'hotywire y igniter I6 has been deen'relgzem l Preferabiy, the mixture shams enter tnef'eibow i portion of the fitting througha generally cylindricalcap 20 having fa plurality of radially `sir-- ranged ports 22 formed by striking! vanes 2&3 -1

inwardly from the side. walls thereof.v The vanes f project inwardly at an 'angle and, therefore,the

mixture passes' from the 4cap with Aaswirling inotion, thus insuring good kturbiilenceat the point of ignition., y j

From the elbow portion `I4 of the `fitting i0, the flame projects into a sheet metalstructure indicated generally by cthe numeralv 26..- This structure is formed of va generally cylindrical internalmember 28, formed preferably ofstainless,

sheet steel, provided with oppositely positioned longitudinally extending slots which form a combustion space 30 and an exhaustl passage32;

fuel and air.- may be supplied by a carburetor speiallyfprovided -for theheater, or it'may be supplied yfrom some alreadypresent source of combustible mixture, such as the supercharger These slots are rgenerally square in crossgsection andextend from end to end of the internal'meinber.V The cylindrical sidewalls extending-be-r tween the combustion space land exhaust passage farei provided with a multiplicityof perforations 34, while the interior.v of the internalzmember is' filled with acoustic dampingI materiali `35, such as glass woolbr stainless steel wool,1forinstance,

of f the enginesV used to propel the internal member. memberisalso Yformed of stainless steel. The

' exhaust passage. I2.

` Y the outlet fitting 48.

y f g`itudinally into this combustion space.

bellows type, comparativelydeeply circumferentially corrugated. heat exchange jacket 38 which isi substantially co-extensive in length with the Preferably, this corrugated corrugated heat exchange jacket 3l has the inner edges of its corrugations spot `or seam welded to the cylindrical surfaces of themuiller member.

28. 'I'he two vmembers thus provide a plurality of inner circumferentially extending passages 3l between the corrugations which communicate with boththe combustion space 3o andthe exhaust passage 32.

A generallyv cylindrical outer shell 4l vencloses the corrugated heat exchange jacket 38 and is arranged with its inner surface closely adjacent the outerjedges of the 'corrugations I'he corrugated jacket 36 and the outer shell 4G, therefore,

corrugations ywhich extend circumferentially of the heater; i vDirectly Opposite the combustionspace 30,' the f outer sheet metal jacket 40 isl shaped to provide la flared rcold air inlet fitting 144extending from f end tosend of the corrugatedjacketthus permi ting cold air flowing inwardly to be distributed over the outer surface oi the portion of the corrugated'jacketlocated directly at the combustion space I0. On the opposite side of the heater,

the shell40 is shaped to provide asimilar outlet fitting 46 leading fromthe shell directly at the l The ends of the internall member 28 andthe form a plurality of outer passages 42 betweenthe n I l 2,403,1s9

ure of combustion will result in the flame being rekindled by the hot re-igniter I8.

The flame thus produced is projected into the combustion space 30 and the hot products of com- -bustion flowoutwardly in both directions into the passages 38 between adjacent con.'o"1itions of4 the corrugated jacket 36. These hot products of combustion flow generally circumferentially in 'opposite'l directions on opposite sides of the heater until they reach rthe exhaust passage 32. they are collected and passed outwardly through the exhaust fitting 56. The perforations 34 in the side walls of the muffler structure 28, `together with the acoustic damping material located within this structure serve to damp out periodici pulsations and, therefore, insure a steady combustion rate, thus effectively preventing the phenomenon known as motor boating.

Thehot products of combustion within the corrugated heat exchange jacket 36 heat the walls of this jacket to a high temperature and this heat is exchanged to the fresh air stream flowing inwardly from a `4bloweror ram to the fitting 44, I the vfresh air impinging directly against the por- ;tion of the corrugated tubing which forms one 'wallof the `combustion space 30. After impinging against this vhigh temperature portion of the `corrugated tubing, the air flows outwardly and `icircumferentially in both directions and leaves Ithe heaterl at the hot air outlet fitting 48.

Theabove arrangement, it should be noted, isv

such that not only does `the coldest air flow over the hottest portion of the corrugated jacket 38,

ibut also this'cold air impinges directly against `the hottest portion thereof. This' is important Y inasmuch as theheat exchange rate between a corrugated heat exchange Jacket` 3c are welded..

to end plates 48' and i0.' preferably formed of stainless sheet steel, which prevent gas communication between the internal and external portions of the corrugated jacket 36., The ends of the surroundingshell 40 are also welded to end plates 62 and 54 which insure that the air entering the coldl air inlettting 44y shall .escape only through The elbow portion I4 of the fitting III is se. curedV to the end plate l2 directly at one end of A-thecombustion space 30 and an opening through the plate 48is madeto permit flame issuing from the elbow portion I4 to project lon' A siml parent to those skilled in the art that ynumerous ilar exhaust fitting 56 is connected to the oppo- `hot surface and an air streamincreases greatly as the angle of attack ofthe air moving against the hot surface approaches 4the vertical. The arrangement thereby insuresthat the portion of the corrugated tubing which forms one wall of the combustion space will receive by' fai` the `greatest cooling effect, thus effectively preventing this portion of the tubing from overheating. It also provides an extremely efficient exchange of heat at the point where the temperature diflferential on opposite sides of the heat exchanger `isthe greatest. i l While I have shown and described a particular embodiment of my inventiomit will be apfmodifications andvariations may be made with-r `out departing from the underlying principles of 1 the invention. I therefore desire, by lthe following claimspto. include within the scope of the invention all such mcdincations and variations fitting. These exhaust gases may be passed through a `pipe connected to the tting to a position outside the airplane, or 'other' vehicle in which the heaterisinstalled.

The'end plates 62 and 54 are provided with -penings through which the attinge In and u pass and these end plates 'arey sealed to the f1ttings 'around these openingsto prevent the escape-of hot air.

The above described device operates in the following manner:

Combustible vgasesy enter 'the fitting I0 and pass through the bundle of tubes I2 and thence outwardly'through the ports 22 in the cap 20 into the elbow portion I4 where they are ignited by the igniter i8. I'he resulting combustion quickly raises the temperature of the reigniter I8 sufllciently'so that the igniter I6 .may be deenergized,4 sinceany subsequent momentary failby which substantially the results'thereof may be l obtained bysubstantially the same 0r equivalent 1 means.

I claim: 1. In an internal combustion heater, a generally cylindrical interior member having re-en-` trant portions in the 'side wall thereof to `form space to` said exhaust passage, saidcorrugated 5ta combustion space and an exhaust passage,

means for supplying a combustible mixture to said combustion space, means for conveying products of combustion from said exhaust passage, a length o f corrugated -tubing surrounding said interior member so that the spaces between corrugations on the inner surface of said tubing together with said interior member provide a plu- 3 rality of passages connecting said combustion tubing also'forming one wall of said combustion space and one wall of said exhaust passage, a

Here

jacket. surrounding said corrugated tubing. said Jacket 'having inlet and outlet openings, andmeans for supplying air to said inlet opening,4

said inlet opening being located substantially directly opposite said combustion spaceso that'air entering through `said vinlet opening Vwill -impinge directly against the portionvof` said corrugated tubing which kforms one wall oifpsaid' combustion 2. In 'an internalrcombustionV heater, an interior member having re-entra'nt portions inthe side walls thereof to form acombuston space and an exhaust passage, meansrfor supplying a combustible rmixture to said combustion space, means for conveying products of combustion from.

said exhaust passagesaid interior lmember being.

hollow and having perforations in" a portion of the side wall thereof, a quantity of acoustic damping material locatedwitliin said"interior member, a corrugatcdqcove'ring' for said interior member so thatthel spaces between corrugations on the inner surface of said covering together 'with said interior member provides, plurality of passages connecting said vcommi-ation space to said exhaust passage, said'corrugated covering also forming one wall of said combustion'space,

ajacket surrounding said corrugatedcovering,`

said jacket having inlet and outlet openings, and means for supplying air tos'aid inlet opening, said inlet openingbeing located substantially directly opposite said combustion` space sothat air I entering through said inlet opening will impinge directly against thev portion of saidcorruwall of said combustion space and'one wall of said exhaust passage, a vjacket surrounding. sald n,corru'gated-tubing, said jacket Shaving inlet and outlet-openings, and meansifor'supplying air to said y inlet opening, said inletI opening beingilocated substantially directly opposite said 'combustionspaceV so that air entering through, said inlet opening.will impinge directlyagainst the portion of said corrugated tubing which forms onewalll of said combustion space.

y 5. Inan-` internal vcombustion-heater, `a. `generally cylindrical interior member having re-entrant` portionsin the side wall thereof to form a combustion space andan exhausty passage,

means'forsupplying vaicombustble :mixture to I said combustion space, means for conveyingproducts ci lcombustion from said exhaust passage, said interior member'being hollow and having perforaticns in a portion of the'side wallr thereof, aquantity of acoustic damping material locat` i` ed within'said interior member, a length of corgated cove-ring which forms one wal1 ofl said combustion space.

3. In an internal combustion heater, an in terior member having re-entrant portions inthe sidewalls thereof to form a combustion space and an exhaust passage, means for supplyingv a combustible mixture to said combustion space, means for conveying products o f combustion from said exhaust passage, a corrugated covering for said interior member'so that. the spaces between corrugations on the innerrsurface of said covering together ywith said interiormember provide a plurality of passages connecting said combus-4 tion' space to said-exhaust passage, said corrugated covering also forming one wall ofsaid combustion space, a Jacket surrounding said corrugated covering, said jacket having inlet and outlet openings, and means for supplying. air to said inlet opening, said inlet openinglbeing located substantially directly opposite said combustion spacel so that air entering said inlet opening will rugated tubing surrounding said interior rmember sc that lthe spaces between corrugations on the,

inner surface of said tubing together with rsaid interior'member provide a plurality of passages i' connecting said combustion space to said exhaust passage, means sealing the ends of said tubing vto the ends of said interior'member, said corru'- gated tubing also forming one yWall ofA said com'- bustion space and one'wall of said'exhaust passage, a jacket surrounding said corrugated tubing, means sealing said jacket at 1 its ends, `saidjacket having inlet and outletr openings, and means for supplying air to saidinlet, opening, said inlet opening` being located substantially directly opposite said combustion space so that air entering said inlet opening will impinge directlyk against the portion of said corrugated tubing which forms one wall of said combustion space.

6. Infan internal combustion heater, an interior member having re-entrant vportions therein to impinge directly against the portion of saidl corrugated covering which forms one wall of said combustion space.

4. In aninternal combustion heatenav-gen-` erally. cylindricalv interior `member having re-entrant portions in the side-walls thereof to formv fcrm a combustion space and an exhaust passage,

means for supplying combustible mixture to` said combustion space, means for conveyind products of combustion from said exhaust passage, a corrugated enclosure for said interior member so arranged with the corrugatitons extending circumferentialiy-that the spaces between corrugations constitute fluid conducting'passages connecting said-combustion space to said exhaust passage, means sealing the ends of the corrugated member` to the ends of the interior member, said corrugated memberalso lforming one wall o'f said combustion space and vone wall of said exhaust -rmssage, a Jacket surrounding said corrugated y membenmeans sealing saidjacket at its ends, said jacket having inlet and outlet openings, and

means'fcr supplying air to said inlet opening, said inlet opening being located closely adjacent said combustion space.

7. In an internal combustion heater, a generallycylindrical interior member having re-entrant vportions in the side wall thereof to forma combustion space and an exhaust passage, means for supplying a combustible mixture to saidcombustion space, means forconveying products of coml bustion from said exhaust passage, a length. of

ber so that the-spaces'between corrugations on the inner surface of saidv tubing togetherwith said interior member provide` a plurality of passages connecting said combustion space to saidexhaust passage, said corrugated tubing also forming one 'Ity tubing to the ends of said interior member, said corrugatedtubing surrounding said interior member with the corrugations extending. circumferenf' tially so that the spaces between the corrugations in the innersurface of said tubing constitute pas-` sages connecting said combustion space to said exhaust passage, means sealing the ends of said corrugated tubing closely adjacent also v A combustion .space and4 one'wall ci' said exhaust passage,ua jacket surrounding said Y corrugated; tubing,means sealingfsaid Jacket at its ends, said .1acke t""having inletA and outlet openings: andi means for supplying air to said inletopening, said inlet opening beinglocated'closely adjacentQsaidI 'combustion'spacel l 8. In an internal combustion heater, a length of generally circumferentiall'y corrugated tubing,`

means tubing to form with said tubing a pluralityof cir-y y cumferentially extending passages, a jacketl ensurface `of said tubing a plural-v ityl of v circumiei'entiallyl means to introduce hot gases between the innen surface ofsthecorrugated tubing andthe means .locatedwithin said tubing.

y and meansy connected to the Jacketto introduce air between said jacket and saidileng'th of corrugated tubing; at a. pointl that at which the hot gases are introduced of' generallyV circumferentially. corrugated tubing, means locatedv within. said lengthcf corrugated tubing to formLwith said tubing a plurality of in` forming one wall of Asaid extending passagesi apaise located within said lengthvofr'gcorrugated closing said length or corrugated tubing to form with-theexterior means'A to maintain'combustion in said inner pas,- sages along a line extending transversely of said corrugations, and' rne'ans connected'to the jacket K ,to introduce air into said outer passages along a line adjacent the rstsaid lir'fie,v

101.7171n an internal combustion heater. a' length of generally circumierentially corrugated tubing,

. means located interiorlyci saidv tubing for forxning with said tubing `a pair of axially extending passages at opposite sides of the heater. from each other and a set of; circumferentially `extending passages betweenrthe` corrugations connecting saidaxially extending passages, means located `exteriorly of said tubingfor forming with said w tubing a second pair ci' axially extending passages at oppsite sides of the heater from eachother and a second set o1' circumferentlally extending'. passages interspersed with'the circumierentially extending passages of *said` rst named set and connecting together the axially `extending passages of said second pair, each of said vaxially ex` tending passages of said second pair being located closely vadjacent oneof the axially extending passages -of said first named pair, nieans connected to said tubing for introducing hot gases `into one of the passages of one ofthe pairs,` and means nez circumferentially extending passages, a jacket enclosing said length of corrugated tubing to form )with theexterior surface of saidtubing a plural#- V ity. or f circumferentially` extending 'passages,

Lconnected to said second named means for introducing fluid to be heated into the adjacent passage oi the second pair. Y l,

HENRY J. lDE N. MccorLUM. 

